clk: imx: cpu clock should be always critical

Add CLK_IS_CRITICAL flag for cpu clock type to
make cpu clock use count correct, as cpu clock
should be always critical.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/imx/clk-cpu.c

@@ -94,7 +94,7 @@ struct clk *imx_clk_cpu(const char *name, const char *parent_name,
 
 	init.name = name;
 	init.ops = &clk_cpu_ops;
-	init.flags = 0;
+	init.flags = CLK_IS_CRITICAL;
 	init.parent_names = &parent_name;
 	init.num_parents = 1;